Multiple choice

The ratio of the speeds of A and B is 2 : 3. B takes 20 minutes less time than A to reach the destination Q, if both started from the same point P, simultaneously. What is the speed of A, if the distance between P and Q is 80 km?

  1. 80 km/h

  2. 75 km/h

  3. 72 km/h

  4. 70 km/h

  5. 60 km/h
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Speed ratio A:B = 2:3, so time ratio A:B = 3:2. Let time for A be 3t and B be 2t. 3t - 2t = 20 mins = 1/3 hour. So t = 1/3 hour. Time for A = 3t = 1 hour. Speed of A = Distance / Time = 80 km / 1 hour = 80 km/h.

AI explanation

Since speed is inversely proportional to time, the ratio of time taken by A and B is 3 to 2. The 1 unit difference corresponds to 20 minutes, making A's total time 60 minutes, or 1 hour. Using the speed formula, the speed of A is 80 km divided by 1 hour, which equals 80 km/h.

Keep practicing — related questions